Preeclampsia still ranks as one of obstetrics major problems. Clinicians typically encounter preeclampsia as maternal disease with variable degrees of fetal involvement. More and more the unique immunogenetic maternal-paternal relationship is appreciated, and as such also the specific 'genetic conflict' that is characteristic of haemochorial placentation. From that perspective preeclampsia can also been seen as a disease of an individual couple with primarily maternal and fetal manifestations. Factors that are unique to a specific couple would include the length and type of sexual relationship, the maternal (decidual natural killer cells) acceptation of the invading cytotrophoblast (paternal HLA-C), and seminal levels of transforming growth factor-beta and probably other cytokines. The magnitude of the maternal response would be determined by factors including a maternal set of genes determining her characteristic inflammatory responsiveness, age, quality of her endothelium, obesity/insulin resistance and probably a whole series of susceptibility genes amongst which the thrombophilias received a lot of attention in recent years.